From c5dcb8919ca048eef84af3eb605f40a41a1a819b Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Sun, 28 Feb 2016 16:28:09 -0500
Subject: research: New "local" testing script

---
(limited to 'research')

diff --git a/research/research6.sh b/research/research6.sh
new file mode 100644
index 0000000..3b7d28a
--- /dev/null
+++ b/research/research6.sh
@@ -0,0 +1,261 @@
+__ESC="$(printf '\033.')"; __ESC="${__ESC%.}"
+ __RS="$(printf '\036.')";  __RS="${__RS%.}"
+ __US="$(printf '\037.')";  __US="${__US%.}"
+__sp=0
+__fn_name=''
+__fn_tu=''
+__fn_vars=''
+__fn_var_vals=''
+__fn=''
+__prev_tu=''
+__prev_vars=''
+__var=''
+__val=''
+__fn_frame=0
+__fn_begin_hooks=''
+__fn_end_hooks=''
+__init_funcs=''
+
+__sp_inc()
+{
+	__sp=$((${__sp} + 1))
+}
+
+__sp_dec()
+{
+	__sp=$((${__sp} - 1))
+}
+
+__frame_set()
+{
+	eval "__frame_${__sp}_name=\${__fn_name}"
+	eval "__frame_${__sp}_tu=\${__fn_tu}"
+	eval "__frame_${__sp}_vars=\${__fn_vars}"
+	eval "__frame_${__sp}_var_vals=\${__fn_var_vals}"
+}
+
+__frame_get()
+{
+	eval "__fn_name=\${__frame_${__sp}_name}"
+	eval "__fn_tu=\${__frame_${__sp}_tu}"
+	eval "__fn_vars=\${__frame_${__sp}_vars}"
+	eval "__fn_var_vals=\${__frame_${__sp}_var_vals}"
+}
+
+__fn_ctxsw()
+{
+	unset IFS
+	case "${__prev_tu}" in
+		${__fn_tu});;
+		?*)
+			# Unset static variables and functions from previous TU.
+			eval "__val=\${__${__prev_tu}_static_vars}"
+			case "${__val}" in ?*)
+				eval "unset \${__${__prev_tu}_static_vars}"
+			;; esac
+			eval "__val=\${__${__prev_tu}_static_fns}"
+			for __fn in ${__val}; do
+				unset -f "${__fn%:*}"
+			done
+	;; esac
+	case "${__fn_tu}" in
+		${__prev_tu});;
+		?*)
+			# Set static variables and function for the current TU.
+			eval "__val=\${__${__fn_tu}_static_var_vals}"
+			eval "${__val}"
+			eval "__val=\${__${__fn_tu}_static_fns}"
+			for __fn in ${__val}; do
+				eval "${__fn%:*}() { ${__fn#*:}; }"
+			done
+	;; esac
+	case "${__prev_vars}" in ?*)
+		unset ${__prev_vars}
+	;; esac
+	eval "${__fn_var_vals}"
+}
+
+__fn_update_vars()
+{
+	unset IFS
+	for __var in ${__fn_vars}; do
+		__val="$(eval "printf '%s' \"\${${__var}}\"" | \
+			sed "s|'|'\\\\''|g;")"
+		__fn_var_vals="${__fn_var_vals} ${__var}='${__val}'"
+	done
+}
+
+__fn_start()
+{
+	# Hooks.
+	unset IFS
+	for __fn in ${__fn_begin_hooks}; do
+		${__fn} ${2}
+	done
+
+	# Old state.
+	__prev_tu="${__fn_tu}"
+	__prev_vars="${__fn_vars}"
+
+	# Update local vars in stack.
+	__fn_update_vars
+	__frame_set
+
+	# Set stack pointer.
+	__sp_inc
+
+	# New state.
+	__fn_name="${2}"
+	__fn_tu="${1}"
+	__fn_vars=
+	__fn_var_vals=
+	__frame_set
+
+	# Switch.
+	__fn_ctxsw
+}
+
+__fn_end()
+{
+	# Hooks.
+	unset IFS
+	for __fn in ${__fn_end_hooks}; do
+		${__fn} ${__fn_name}
+	done
+
+	# Old state.
+	__prev_tu="${__fn_tu}"
+	__prev_vars="${__fn_vars}"
+
+	# Set stack pointer.
+	__sp_dec
+
+	# New state.
+	__frame_get
+
+	# Switch.
+	__fn_ctxsw
+}
+
+__tu_end()
+{
+	# Save TU static vars.
+	unset IFS
+	for __var in $(eval "printf '%s' \"\${__${__tu}_static_vars}\""); do
+		__val="$(eval "printf '%s' \"\${${__var}}\"" | \
+			sed "s|'|'\\\\''|g")"
+		eval "__${__tu}_static_var_vals=\"\${__${__tu}_static_var_vals}\
+			${__var}='\${__val}'\""
+		unset ${__var}
+	done
+
+	__tu=''
+}
+
+__stack_trace()
+{
+	__fn_frame=0
+	while [ ${__fn_frame} -le ${__sp} ]; do
+		eval "printf '%s\n' \"\${__frame_${__fn_frame}_name}\""
+		__fn_frame=$((${__fn_frame} + 1))
+	done
+}
+
+__local()
+{
+	unset IFS
+	for __var in "${@}"; do
+		case "${__var}" in
+			*=*)
+				__val="${__var#*=}"
+				__var="${__var%%=*}"
+				;;
+			*)
+				__val=''
+				;;
+		esac
+		case "${__var}" in [!A-Za-z_]* | *[!0-9A-Za-z_]*)
+			printf 'Syntax error: %s %s\n' \
+				'illegal static variable name:' "${__var}" >&2
+			exit 1
+		;; esac
+		eval "${__var}=\${__val}"
+		__fn_vars="${__fn_vars} ${__var}"
+	done
+}
+
+__static()
+{
+	case "${__tu}" in '')
+		printf 'Error: Cannot declare static variables in functions' >&2
+		exit 1
+	;; esac
+	unset IFS
+	for __var in "${@}"; do
+		case "${__var}" in
+			*=*)
+				__val="${__var#*=}"
+				__var="${__var%%=*}"
+				;;
+			*)
+				__val=''
+				;;
+		esac
+		case "${__var}" in [!A-Za-z_]* | *[!0-9A-Za-z_]*)
+			printf 'Syntax error: %s %s\n' \
+				'illegal static variable name:' "${__var}" >&2
+			exit 1
+		;; esac
+		eval "${__var}=\${__val}"
+		eval "__${__tu}_static_vars=\"\${__${__tu}_static_vars} \
+			${__var}\""
+	done
+}
+
+__fn_begin_hook()
+{
+	__fn_begin_hooks="${__fn_begin_hooks} ${1}"
+}
+
+__fn_end_hook()
+{
+	__fn_end_hooks="${__fn_end_hooks} ${1}"
+}
+
+__init()
+{
+	__init_funcs="${__init_funcs} ${1}"
+}
+
+EOF(){ :; }
+
+#: <<'EOF'
+################################################################################
+# TU 0
+################################################################################
+__tu=tu0
+__tu0_static_vars=
+__tu0_static_var_vals=
+__tu0_static_fns=
+
+a()
+{
+	__fn_start tu0 a
+	__local v=1
+	echo "v (should be 1): $v"
+	b
+	echo "v (should be 1): $v"
+	__fn_end
+}
+
+b()
+{
+	__fn_start tu0 b
+	echo "v (should be empty): $v"
+	__fn_end
+}
+
+__tu_end
+
+a
+EOF
--
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